SIFT Mechanical Comprehension Questions and Answers

Question 1

In the pulley system shown, a 100 lb weight is being lifted. Assuming the system is frictionless, what is the minimum force (F) required to lift the weight?

Accepted Answer

25 lbs

Answer

100 lbs

Answer

50 lbs

Answer

20 lbs

Question 2

A smaller gear with 15 teeth is driving a larger gear with 45 teeth. If the smaller gear completes 3 full rotations, how many rotations will the larger gear complete?

Accepted Answer

1 rotation

Answer

3 rotations

Answer

9 rotations

Answer

1.5 rotations

Question 3

Which of the following scenarios describes a second-class lever?

Accepted Answer

A person using a wheelbarrow to move soil.

Answer

A pair of scissors cutting paper.

Answer

A person using a fishing rod to lift a fish.

Answer

A seesaw with two children on it.

Question 4

According to Bernoulli's principle, if the speed of a fluid moving through a pipe increases, what happens to the pressure within the fluid?

Accepted Answer

The pressure decreases.

Answer

The pressure increases.

Answer

The pressure remains constant.

Answer

The pressure is unrelated to the speed.

Question 5

A hydraulic lift uses two pistons. The input piston has an area of 2 square inches, and the output piston has an area of 20 square inches. If a force of 50 lbs is applied to the input piston, what is the maximum weight the output piston can lift?

Accepted Answer

500 lbs

Answer

5 lbs

Answer

100 lbs

Answer

200 lbs

Question 6

If Gear A rotates clockwise, what will be the direction of rotation for Gear C?

Accepted Answer

Clockwise

Answer

Gear C will not rotate.

Answer

Counter-clockwise

Answer

The direction cannot be determined.